A growing number of persons living with HIV/AIDS are aged 50 or older. Many of these late middle-aged and older persons report difficulty maintaining strict adherence to antiretroviral regimens. This is important because consistent adherence to complex HIV medication regimens is critical for achieving and sustaining improved health outcomes. However, HIV adherence interventions to date have not specifically targeted this age group. Tailored interventions designed to meet the unique needs of late middle-aged and older adults are urgently needed. We are proposing to design and pilot test an experimental intervention for increasing adherence to antiretroviral treatment among late middle-aged and older persons living with HIV. Intervention development will be guided by the transtheoretical model of behavior change and multi-component intervention strategies combining motivational interviewing techniques with behavioral skills training. The proposed investigation will be conducted in four stages over the two-year study period. A sequence of planning and developmental activities will include: (1) conducting focus groups with late middle-aged and older persons taking antiretroviral medications to assess adherence issues and intervention preferences; (2) designing and testing the feasibility and acceptability of individual-level and group-level adherence intervention formats for persons living with HIV who are 50 years of age or older; (3) pilot testing of intervention efficacy; and (4) preparing intervention manual materials which will form the basis for a subsequent proposal of a full-scale randomized clinical trial of the experimental intervention. There is a great need for effective adherence interventions and feasible methods for delivering them to underserved HIV infected populations. Development of a tailored intervention designed to enhance skills and motivation for antiretroviral adherence among persons aged 50 and older living with HIV AIDS will help address this need. This planning project constitutes the next phase of study necessary to improve antiretroviral treatment adherence in late middle-aged and older persons living with HIV.